There are numerous requirements for a radio receiver which can cover an extremely wide frequency band while guaranteeing a high probability of intercept for any signal within this band. This is particularly true with regard to electronic warfare receivers which are used to receive a signal that does not have a previously known carrier frequency.
Receiver systems have been developed which utilize a sweeping local oscillator signal to provide a greater reception bandwidth. Such receivers are shown in U.S. Pat. No. 4,204,165 to Ready and in U.S. Pat. No. 2,954,465 to White. It has been found, however, that there are substantial practical limitations to the intercept bandwidth of such systems. The maximum bandwidths are typically limited by a specific circuit common to the entire receiver. This can take the form of a maximum rate for a digital sampler or the maximum possible IF bandwidth. Due to these restrictions there is a limit to the maximum bandwidth which can be received by such receivers while guaranteeing a very high probability of intercept.
In view of the need for a receiver system having an extremely wide intercept bandwidth, there exists a requirement for a receiver which can be incrementally expanded channel by channel to proportionately widen the intercept bandwidth while the system is not limited to the maximum performance for a single circuit or component.